At this point, I don't think you do. I have no real explanation of this aside from, that's how it is. I have Exchange 2010 in my environment and when I run Get-PSSnapin -registered I receive:
Name : Microsoft.Exchange.Management.PowerShell.E2010
PSVersion : 1.0
Description : Admin Tasks for the Exchange Server
Name : Microsoft.Exchange.Management.PowerShell.Setup
PSVersion : 1.0
Description : Setup Tasks for the Exchange Server
Name : Microsoft.Exchange.Management.Powershell.Support
PSVersion : 1.0
Description : Support Tasks for the Exchange Server